This invention relates to controls for electrical apparatus and, more particularly, to circuit control devices for use with electronic image display screens having the capability of receiving operator input as well as displaying images, data, and other meaningful visual outputs.
The concept of combining electronic image display screens with operator input sensor apparatus correlated to the images presented on the display screen is well known in the prior art, as exemplified by the U.S. patents issued to the present inventor:
U.S. Pat. No. 5,572,239
U.S. Pat. No. 5,977,955
U.S. Pat. No. 5,805,146
U.S. Pat. No. 5,805,145
U.S. Pat. No. 5,936,613
U.S. Pat. No. 5,774,115
The technology for operator input sensor apparatus, commonly known under the overarching term xe2x80x9ctouch screenxe2x80x9d, actually comprises any one of several schemes for detecting and transmitting operator inputs related to the images presented on the associated display screen. These devices may employ detection based on optical, capacitance, magnetic, or resistance effects. Many of these devices employ a stylus or pen to impart the operator""s control input to the touch screen device. Typically, the stylus incorporates an electronic signaling circuit that either receives or emits a signal that is used by the touch screen device to determine the position of the stylus on the touch screen, and thus correlate the input position with the corresponding image portion of the display screen. The electronic circuit in the stylus receives power from either an internal battery or an external power supply connected by cable to the stylus.
Both of these conventional power arrangements suffer from primary drawbacks. The internal battery must be replaced periodically, and the diminishing voltage of a failing battery may affect the functioning of the sensor system. A connector cable joined to the stylus is an encumbrance to free use of the stylus, and is a snag hazard on a desk or work table. Thus the prior art is deficient in providing a powered sensor stylus that is free of these drawbacks.
The closest known prior art in this regard is described in U.S. Pat. No. 5,936,613, issued Aug. 10, 1999 to the present inventors. This invention discloses a knob-like controller supported by a base member secured to a display screen, and a photovoltaic cell disposed in the base member to receive light from the screen and generate electrical energy that powers the signal circuit of the knob-like controller. This device can only be implemented by use of a device placed in front of a display, either on a superstrate in front of a display or on the display itself, which may be a detriment in some graphic display situations: i.e., rapidly changing image content, or the like. Thus the prior art does not include a powered touch screen input stylus that is perpetually self-powered and free of any attachment to the touch screen itself. Likewise, U.S. Pat. No. 5,774,115, issued Jun. 30, 1998 to the present inventors, discloses powered touch screen input devices that receive transmitted power without resorting to batteries or electrical power connections to the touch screen system, but these devices are also mechanically secured to the touch screen itself.
The present invention generally comprises a powered touch screen input device that is perpetually self-powered and free of any mechanical connection to the touch screen itself. In one aspect, the input device includes at least one photovoltaic cell supported thereon and disposed to receive light from the display screen associated with the touch screen device. The photovoltaic cell is connected to the electronic signaling circuit disposed within the input device. This signaling circuit may comprise a radio frequency transmitter, or a light emitting diode or laser, or a magnetic field generator, or any other circuit that is adapted to interact with any touch screen device known in the prior art. The input device is adapted to be wielded by the user of the touch screen and to be placed in contact or close spacing to the touch screen device. Position and movement of the input sensor are correlated by a software driven processor with the images generated on the display screen associated with the touch screen system. At the same time, the photovoltaic cell(s) of the input device are connected to power the onboard signaling circuit of the input device, so that all necessary power for the input device is delivered whenever the device is situated proximate to the display screen, without resort to batteries, cables, or tethers of any kind.
In another aspect, the invention comprises a stylus for use with a touch screen device associated with a display screen. The stylus includes an electronic signaling circuit designed to interact with the touch screen device, whereby the position and movement of the stylus on the touch screen may be correlated with the image content generated by the display screen. The stylus includes a proximal tip connected to the electronic signaling circuit to generate or receive radiation from the touch screen and interact therewith. The stylus further includes at least one photovoltaic cell disposed adjacent to said proximal tip and disposed to receive light emanating from the display screen. The photovoltaic cell(s) is connected to power the electronic signaling circuit, so that no batteries or mechanical connections to any extrinsic power supply are required.
The stylus system may be scaled so that the photovoltaic cell(s) provide sufficient power to the electronic signaling circuit whenever the stylus tip is brought into proximate contact with the touch screen device. Thus the stylus is self-powered whenever it is brought into use, but is otherwise not mechanically or electrically connected to the touch screen device.
In a further embodiment, the invention provides a powered touch screen input device that is powered by electrical energy transmitted to the input device from the touch screen system. The touch screen system includes an antenna that radiates RF energy in the area immediately about the touch screen itself. The input device includes a coil that acts as an receiving antenna to receive the RF energy, which is rectified and smoothed and connected to power the electronic signaling circuit. The broadcast antenna may comprise a coil or coils arrayed about the periphery of the touch screen system, or disposed at the back surface of the touch screen itself. The receiving coil is tuned to optimize reception of the RF energy, and may be placed in the bezel or barrel of the stylus described above. The RF power transmission to the input device results in an input device that is perpetually self-powered when it is brought into proximity to the touch screen system, and which needs no mechanical or electrical connection to the touch screen system.
The RF transmission system may also be combined with the photovoltaic cells described above, whereby the input device is assured of sufficient power for operation.